Most common cause of projectile vomiting?

RRB Staff Nurse Mumbai-2015

Child Health Nursing (Pediatrics)

Easy

Appeared in: RRB Staff Nurse Mumbai-2015

Explanation

Pyloric stenosis is the most frequent cause of gastric outlet obstruction in infants, classically presenting with projectile vomiting.
The condition involves hypertrophy of the circular muscle of the pylorus, which physically blocks food from leaving the stomach.
The vomiting is characteristically non-bilious because the obstruction is proximal to the ampulla of Vater, where bile enters the duodenum.
It typically presents in infants aged 2-8 weeks and is more common in males.
A key physical finding is a palpable, firm, olive-shaped mass in the epigastrium.

Option A: SAIO (Small Intestinal Obstruction) typically causes bilious (green-stained) vomiting because the obstruction is usually distal to the entry of the bile duct into the duodenum. While it causes vomiting, it is not the most common cause of projectile vomiting in this age group.
Option C: Intussusception is characterized by the telescoping of one part of the intestine into another. The classic triad of symptoms is intermittent colicky abdominal pain, a sausage-shaped abdominal mass, and 'currant jelly' stools (stools mixed with blood and mucus). Vomiting is a feature but is not typically the primary or most classic projectile symptom.
Option D: Hirschsprung's disease is a congenital condition involving a lack of nerve cells in the distal colon, leading to functional obstruction. The primary symptoms are failure to pass meconium at birth, severe constipation, and abdominal distension. Vomiting can occur but is usually a later sign and is often bilious.

Visual 1: Anatomical Diagram - An illustration showing the hypertrophied pyloric muscle between the stomach and duodenum, highlighting the narrowed gastric outlet. This helps visualize the pathophysiology of pyloric stenosis.
Visual 2: Comparison Chart - A table comparing the key signs and symptoms (vomit type, stool character, abdominal findings, age of onset) of Pyloric Stenosis, Intussusception, Hirschsprung's Disease, and SAIO.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Differential diagnosis of projectile vomiting in infants as background academic context rather than a clinical decision trigger.
A nurse's ability to differentiate between causes of vomiting is critical for early diagnosis and intervention. Recognizing non-bilious projectile vomiting as a hallmark of pyloric stenosis prompts urgent referral.
Pre-operative management is a key nursing responsibility, focusing on correcting dehydration and electrolyte imbalances (hypochloremic metabolic alkalosis) with IV fluids to stabilize the infant for surgery (pyloromyotomy).
Post-operative nursing care involves a careful, graded feeding plan to prevent stress on the surgical site and monitoring for any signs of complications.

How to Approach the Question

First, identify the key symptom in the question: 'projectile vomiting'. This is a very specific and forceful type of vomiting.
Next, consider the term 'most common cause'. This requires you to recall the epidemiology of various pediatric GI conditions.
Evaluate each option based on its classic presentation. Pyloric stenosis is the textbook cause of projectile, non-bilious vomiting in early infancy.
Differentiate from other options: SAIO, intussusception, and Hirschsprung's disease typically present with other dominant symptoms (bilious vomiting, 'currant jelly' stools, or severe constipation, respectively) and are not the most common cause of this specific vomiting pattern.
Select the option that best matches the classic description of projectile vomiting in an infant.

Concept Tested & Keywords

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